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Galactic black hole transients H1743-322 and 4U 1630-47 in outburst

ATel #1348; Kalemci, E (Sabanci Un.), Tomsick, J. A. (SSL/UC Berkeley), Yamaoka, K. (Aoyama Gakuin Un.), Ueda, Y. (Kyoto Un.)
on 4 Jan 2008; 08:00 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Emrah Kalemci (ekalemci@sabanciuniv.edu)

Subjects: Radio, Infra-Red, Optical, X-ray, Gamma Ray, Request for Observations, Black Hole, Transient

Referred to by ATel #: 1349, 1352, 1378, 1384, 1385, 1387, 1414, 1739

The ASM on RXTE showed increased activity from H1743-322, a Galactic black hole transient whose last outburst occurred in 2003. On December 19th, the ASM count rate increased to 14.45 cts/s (200 mCrab), and since then the ASM measurements on December 26th, 29th, 30th 2007 and January 1st 2008 vary between 200 and 400 mCrab (errors were about 30-40 mCrab). There is no other measurement since January 1st but the trend indicates an outburst.

The ASM also indicates activity from the black hole transient 4U 1630-47. On December 26, 2007, the flux was around 100mCrab, and increased steadily to 200 mCrab by January 2, 2008.

Multiwavelength follow up observations are encouraged for both sources.